<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>菜鸟教程(runoob.com)</title>
</head>
<style>
    .tooltip {
        position: relative;
        display: inline-block;
        border-bottom: 1px dotted black;
    }

    .tooltip .tooltiptext {
        visibility: hidden;
        width: 120px;
        background-color: black;
        color: #fff;
        text-align: center;
        border-radius: 6px;
        padding: 5px 0;
        position: absolute;
        z-index: 1;
        top: -5px;
        right: 110%;
    }

    .tooltip .tooltiptext::after {
        content: "";
        position: absolute;
        top: 50%;
        left: 100%;
        margin-top: -5px;
        border-width: 5px;
        border-style: solid;
        border-color: transparent transparent transparent black;
    }
    .tooltip:hover .tooltiptext {
        visibility: visible;
    }
</style>
<body style="text-align:center;">

<h2>左侧提示框/右侧箭头</h2>

<div class="tooltip">鼠标移动到我这
    <span class="tooltiptext">提示文本</span>
</div>

</body>
</html>